Officials said the plane had taken off from Nashua and was en route to Laconia.

State police Lt. Chris Wagner said the plane clipped a light a pole before the crash. Much of the light pole is above tree level.

"Six or eight feet of the wing came off and knocked down the light," witness David Nylen said.

Witness Donna Derocher said she saw the plane flying very close to trees before it crashed.

"It just started to come too close to the tree line," she said. "It was teetering, rocking too much back and forth. There was definitely something wrong."

The front end of the plane was heavily damaged from crashing into a guardrail. No cars were hit in the crash.

"Pieces are flying off of it," truck driver Bruce Hunkins said. "It looked like it was in slow motion, like it had no weight at all. (It) just didn't look real."

Hunkins saw the plane coming down in front of his rig.

"It was going to land right on top of me. I hit the brakes, and it landed right in front of me and slid off the road," Hunkins said.

The ramp from Interstate 93 north to Interstate 293 south was closed, and Interstate 93 was down to one lane of travel. By 4:30 p.m., the ramp was reopened.

The Beechcraft plane, which is registered out of Rhode Island, was involved in an emergency landing two years ago when its landing gear wouldn't deploy.

"In that case, the airplane landed, couldn't get the landing gear down, and he landed with the gear up," Nashua Airport Manager Royce Raykin said. "That's not uncommon. That happens, and you can land an airplane with the gear up and walk away from it, but we have no idea today."

Herman Hassinger was a well-known architect and president of "Herman Hassinger Architects" in New Jersey. He designed the Crestview building at Franklin Pierce University in 1994.

He was a trustee for the New Hampton School in New Hampton and has been on the school's board of directors since 1978, which was set to meet this weekend. He also served on several boards and committees in Block Island, R.I.

Hassinger was an experienced pilot, but authorities wouldn't immediately say if we was behind the controls of the plane.

It's also unclear why the plane turned around, but authorities said it's a good thing traffic on the interstate was light.

"New Hampshire State Police is following up with the FAA, NTSB, as well as N.H. Aeronautics to determine what happened," New Hampshire State Police Lt. Christopher Wagner said.

Officials at Nashua Airport said the Hassingers were well-known, and they frequently stopped by Infinity Aviation during short layovers. Mechanics said they didn't have any work done on the plane or even refuel Thursday.

Raykin said conditions were perfect for flying, and it's hard to say what may have caused the crash.

"The plane was pretty much intact from what I saw. I've seen (crashes), (like) the one in Lebanon, where you could hardly even distinguish it was an airplane," Rankin said.

The New Hampton School released a statement about the crash Thursday night.

"Herman was the longest-serving trustee on the board, and he contributed in so many ways. He was incredibly generous with his time and thoughtful of the student experience at New Hampton. Our hearts go out to the Hassinger family," the statement indicated.

The Hassingers had four children, eight grandchildren and at least two great-grandchildren, according to an online profile.